Knowledge of building code is required for most building design licenses. However, designers often find the process confusing and overwhelming. The cognitive load theory suggests dividing information between visual and verbal formats reduces working memory burden, while concept mapping and mobile apps enhance learning. This study tests the usefulness of the Building Code Calculator; a new mobile application designed to improve building code knowledge and reduce cognitive load in design education. This prototype provides a visual structural knowledge guide, and it incorporates calculation features associated with the rationale behind the calculations. Senior interior design students performed building code tasks using conventional methods and the app. Stress levels were measured using galvanic skin response, heart rate monitoring, brain oxygenation, and survey responses. The findings suggest that the Building Code App effectively accelerates task completion while simultaneously reducing students' stress levels.